1. Field of the Invention
The present invention relates to an apparatus for producing an organic EL display device, and a process for producing an organic EL display device. More specifically, the present invention relates to a producing apparatus making it possible to produce an organic EL display device capable of suppressing the generation of non-luminescence areas or non-luminescence spots, which may be referred to dark spots, in pixels; and a process for producing such an organic EL display device.
The “EL” described in the claims and the specification is an abbreviation of “electroluminescence”.
2. Description of the Related Art
Hitherto, various sealing means and moisture-proof means in organic EL display devices have been investigated to exclude the effect of moisture in the atmosphere and suppress the generation of non-luminescence areas, non-luminescence spots and the like in luminescence areas at the time of driving the devices.
It is also studied that an organic EL display device is produced without being exposed to the atmosphere. Such a producing apparatus is disclosed in JP-A-No. 8-111285, 10-214682 or 10-335061.
As illustrated in FIG. 20, in a producing apparatus 250 for an organic EL display device disclosed in JP-A-No. 8-111285, plural vacuum chambers 111 to 116 for working are connected to the periphery of a vacuum device 110. A movable arm 102 for carriage is disposed inside the vacuum device. Thus, a substrate 104 can be moved while the vacuum device and the working vacuum chambers are under a reduced pressure condition.
Therefore, respective layers of an organic EL element can be formed on the substrate in the respective working vacuum chambers while the substrate is passed through the single vacuum device. In other words, an organic EL display device can be produced without being exposed to the atmosphere from the respective film-depositing step to the step of forming a protective film.
As illustrated in FIG. 21, an apparatus for producing an organic EL display device disclosed in JP-A-No. 10-214682 comprises independent 1st-nth working vacuum chambers 222a to 226a, and 1st-nth carrying vacuum chambers 222 to 226 connected to the working vacuum chambers through gate valves 222d to 226d, respectively. The carrying vacuum chambers 222 to 226 are horizontally connected to each other through gate valves 222c to 227c. A substrate and so on can be transferred from a first dry box 221, which is an inlet, to a second dry box 227, which is an outlet, by means of robot arms 222b to 226b set up in the respective carrying vacuum chambers.
Accordingly, it is possible that respective layers of an organic EL element are formed in the respective working vacuum chambers and the unfinished organic EL element can be successively moved in the respective working vacuum chambers through the carrying vacuum chambers while the working vacuum chambers are in a reduced pressure state. In short, an organic EL display device can be produced without being exposed to the atmosphere from the step of depositing its films to a sealing step.
As illustrated in FIG. 22, an apparatus for producing an organic EL display device, disclosed in JP-A-No. 10-335061, comprises a vacuum chamber 315, a vacuum device 307 connected to the vacuum chamber, a carrying and pressing means 316 for carrying an organic EL element 309 or a sealing member 312 in the vacuum chamber, a hardening means 311 for hardening an adhesive layer 313 between the organic EL element 309 and the sealing member 312.
It is therefore possible to form respective layers of the organic EL element inside the vacuum chamber 315 and further harden the adhesive layer 313 with the hardening means (ultraviolet-ray exposure device) 311 in the state that the sealing member 312 prepared inside the vacuum chamber is positioned and then pressed from the above by means of the carrying and pressing means 316. In short, an organic EL display device can be produced without being exposed to the atmosphere from the step of depositing its films to a sealing step.
However, in the organic EL display device producing apparatus disclosed in JP-A-No. 8-111285, the number of the working vacuum chambers (vapor-depositing chambers or sputtering chambers) arranged around its vacuum tank is as large as, for example, five. Thus, a problem that the producing apparatus becomes large-sized arises.
No unit for removing water from an organic EL wafer wherein a transparent element, an organic film and so on are formed on a glass substrate is set up. It is therefore difficult to lower the water content in an organic luminescence medium in the resultant organic EL display device. Thus, a problem that dark spots as non-luminescence areas are easily generated arises.
A problem that sealing is insufficient is also caused since a protective film is formed on the organic EL wafer and subsequently the resultant is exposed to the air.
The organic EL display device producing apparatus disclosed in JP-A-No. 10-214682 comprises the 1st-nth working vacuum chambers, the 1st-nth carrying vacuum chambers and the first and second dry boxes, and they are horizontally connected to each other. Thus, this apparatus has a problem that it becomes markedly large-size.
This producing apparatus has the first dry box. However, the first dry box is a space where the water content is controlled into a low value and no heating device is set up. Thus, water contained in a substrate and so on cannot be positively removed.
Therefore, it is difficult to lower the water content in the organic luminescence medium in the resultant organic EL display device. Thus, it has still been difficult to suppress the generation of dark spots and so on as non-luminescence areas and obtain a high luminescence brightness for a long time.
The organic EL display device producing apparatus disclosed in JP-A-No. 10-335061 has no water-removing means, that is, no function for removing water contained in a substrate and so on positively. Therefore, it is difficult to lower the water content in the organic luminescence medium in the resultant organic EL display device. Thus, it has still been difficult to suppress the generation of dark spots and so on as non-luminescence areas and obtain a high luminescence brightness for a long time.
As illustrated in FIG. 23, an organic EL display device producing apparatus 400 disclosed in JP-A-No. 2000-133446 comprises load side receipt chambers 412 and 413, a load side normal-pressure carrying chamber 411, a load chamber 421, a vacuum carrying chamber 431, film-depositing chambers 432 to 435, an unload chamber 441, an unload side normal-pressure carrying chamber 451, unload side receipt chambers 452 and 453, and an airtight working chamber 454, and is characterized in that an inert gas atmosphere having a water content of 100 ppm or less is filled at least into the unload chamber 441 and the unload side normal-pressure carrying chamber 451. JP-A-No. 2000-133446 also discloses that in the load side receipt chambers 412 and 413, a substrate and any organic material on the substrate are preferably heated to remove water from them.
However, in the disclosed organic EL display device producing apparatus, the position into which the substrate is carried and the position in which the substrate is heated are common. Therefore, the apparatus has a problem that in the case in which the load side receipt chamber is once heated, a next substrate cannot be carried thereinto until the temperature of the load side receipt chamber falls. Since the position into which a substrate is carried and the position in which the substrate is heated are common and further the load side normal-pressure carrying chamber is arranged after the heated load side receipt chamber, it is difficult to reduce the pressure of the load side receipt chamber, cool the chamber, or set up a precision balance therein. Therefore, a problem that it takes much time to remove water from the substrate and so on sufficiently or carry out a dehydration step arises.
Thus, it is suggested that plural load side receipt chambers are disposed. However, there arise problems that the whole of the producing apparatus including a heating device and a precision balance becomes large-scaled and the performances of resultant organic EL display devices are scattered because of a scattering in heating temperatures in the load-side receipt chambers.
Furthermore, in the disclosed organic EL display device producing apparatuses, the position into which a substrate is carried and the position in which the substrate is heated are common. Therefore, it is impossible a that the position where the substrate is heated and the position where the substrate is cleaned are conversely made common. Thus, the apparatuses have problems that the whole of the apparatuses increasingly becomes large-scaled and further the substrate absorbs water at the time of the transfer of the substrate from the substrate-heating position to the substrate-cleaning device so that dehydration effect is lowered.
Thus, the inventors eagerly made further investigations on such problems. As a result, it has been found that by setting up a water-removing unit separately from the position into which a supporting substrate is carried and removing water positively from the substrate and so on through heating treatment, the water content in an organic luminescence medium can be markedly lowered, so that the generation of dark spots and the like, as non-luminescence areas, around pixels can be greatly suppressed.
Therefore, an object of the present invention is to provide an organic EL display device producing apparatus making it possible to obtain effectively an organic EL display device capable of suppressing the generation of dark spots and the like even if the device is driven for a long time.
Another object of the present invention is to provide an organic EL display device producing process making it possible to obtain effectively an organic EL display device capable of suppressing the generation of dark spots and the like even if the device is driven for a long time.